Wednesday, August 27, 2025

Index - of sorts anyway. Think of it as a guide.

 Bikes



Clutch


Electrical


Engines and Dyno runs


Exhaust


Maintenance


Suspension



Tuning - Carby

Tuning - Fuel Injection


Moto Guzzi


Cagiva


MV Agusta


Stuff


.

Things that can cause a dragging clutch.

I've long intended to make a video about Ducati dry clutches, but the opportunity has evaded me thus far.  I do have a written "diagnosis" sheet which I'll neaten up and post here so I can link to it easily.  I'll steal some photos from the net to fit the points.  As follows:

If you can't select neutral with the engine running, but it's easy with the engine off, it means the clutch is dragging.  Simple as that.

IME, things that can make it drag, from the top:
 
Air in the system.  Not as hard to bleed as many make out.  If it's hard to bleed, turn the bars to the right and tilt the bike over so that the tip of the lever is the highest point and gently pull the lever in and out.  This will work any air in the hose up to the master and out.  If it's a coffin style master you can spray fluid everywhere doing this, so maybe put the cap on.  Or cover the bodywork, screen, dash, etc first.  Big plastic bags work well.  

You can feel the lever get harder if there's air coming out.  Slow pulls, a few fast, slow, tap the hose, make sure there's no high point loops in the hose, etc.

Some people add bleeder nipples at the master cylinder outlet and bleed there as well.  Never seen the need myself - I just lean the bike over to the right more.  

You can use a syringe to push fluid in from the slave bleeder and up to the top.  Certainly one way to do it, and may dislodge air you can't get to otherwise (possibly more brake based, especially ABS unit).  Just don't make a mess as it comes out the top.

I use a vacuum bleeder to suck the fluid through, as it's faster and works well.  But there's nothing wrong with just opening the bleeder and pumping the lever to push the fluid through.
 
Worn lever pivot.  Either the hole in the lever or the actual pin itself.  With the older style large hollow pin lever pivot, the pins can wear a lot on bikes that don't get lubed, as can the lever.  You can remove the pin, clean and lube and spin it 180 degrees to get a fresh side.  On these masters, the pin pushing the piston can also wear shorter.


On masters with the smaller, solid pin, the barrel on the end of the piston pushrod can wear in the lever, I've seen lots almost worn through the lever.  

The piston pushrod itself screws into the barrel, and underneath there is a grub screw that locks the pushrod in place.  If the grub screw is loose, the pushrod will generally wind itself out, increasing the free play.  Often, with replacement levers this grub screw is loose or not there, so always check that.
 
Conversely, if you want to adjust or remove the pushrod, you need to make sure the grub screw is loose.  It’s a 1mm hex key, so tiny.  and sometimes loctited in, so you might need some heat to make it move.  Can be infuriating.



Crap aftermarket levers.  Either giving excessive free play or no free play.  Might be adjustable, maybe not.  Some of the crap I see is just truly craptacular.  
 
Also, make sure you actually have free play.  And that the piston is returning to the end of its stroke and opening the compensating port.  That’s the little hole closest to the lever end.  B in the photo below.  If fluid can’t flow out of the system, it also can’t get in, and this can cause issues as well when trying to bleed.  If in doubt, give it as much free play as possible, or even remove the lever to see if that suddenly changes the feel, or drops the fluid level.  The fluid should rise a little when you pull the lever in.  On coffin masters, it’ll spurt fluid out of the compensating port, so be careful.

I've brought up the free play thing many times on forums, etc, and lots of people just don't get it.  Or get very offended, like I've insulted their manhood.  Seriously - make sure you have free play.  Add more, just in case it helps.  If I have one that just won't bleed, I often remove the lever to make sure.  Even if it was fine last week - add more free play.  You'd be amazed how many times it just works.


This is the adjuster on a big pivot lever.  From the factory they often had the flat blade screwdriver slot in the end of the adjuster filled with glue so you couldn't adjust it and mess it up.


Aftermarket clutch slaves.  Usually have a larger in piston diameter, increasing the hydraulic ratio to soften the lever, but decreasing the slave piston travel correspondingly.  It's a ratio trade off.  If the slave is a lot larger, the pressure plate might not be lifting far enough.  Move the lever out, pull it in further, etc.
 
While not really drag specific.  Worn pushrods, slave pistons and seized pushrod bearings in the pressure plate.  The seized bearing will spin the pushrod and it'll wear away and into the piston.  I had a 900ss in once that the owner had had long time clutch issues with from new (tip - it's not the bike, it's you) when it was maybe 15 years old.  It needed a new pack and once fitted I pumped the lever and the slave piston and pushrod were so worn that the piston popped out of the slave body.  Scared the shit out of me when it went bang.
 
Warped steel plates.  There should be 1 x 1.5mm "spring" steel plate, which is conical and if you put it on a flat surface and press the outer edge (if it's the right way up) the opposite edge will lift.  The 7 friction plate pack pre 1100/1098 models had would also have 8 x 2mm flat steel plates.  The thickness of those packs from Ducati is nominally 38.5mm.  The 1100/1098> packs with 8 frictions and 10 steels will usually have some 1.5mm flat steel plates to reduce the overall thickness due to the extra plates. From memory they're around 40.5mm, but done hold me to that.  Pack thickness itself, as long as it's not stupid either way, isn't an issue IMO.  Less thickness reduces spring preload and thereby lever effort.  More thickness and the friction plates might come out the end of the basket and not go back in.

Using a very flat surface, check the rest of the steel plates to see if any of the other plates behave like the spring plate, flipping them to check both sides.  If they do, they're warped and need replacing.  You can't get around them being warped.  You may also find someone has fitted more than 1 of the 1.5mm spring plates for some reason, valid or not.  There was a DP slipper for 1198 that liked 4 of them.  Really don't understand how it worked without dragging like crazy, but I've done it, so I know it was fine.

As above, there are also flat 1.5mm steel plates, used in the 1098 onwards 8 friction plate packs and the Surflex sintered 8 friction plate packs that used to come in SP / SPS/ R models, so don't think any and all 1.5mm steel plates are springs.  Unless you have a stash of good steel plates, the only place to get them is a new complete pack.  OEM, Barnett, Ducabike, Newfren, Adige and Surflex all make packs.  Aluminium plates in a steel basket will make the plates sacrificial - it's what I tend to do these days.
 
Hub wear  - the centre part the plates go over.  Watching from above, pull the lever in and see if the spring caps move outwards as the lever free play takes up, then stop and then the pressure plate starts lifting off the pack.  If so, the large star like washer at the front of the hub is eating its way into the hub.  Pretty common.  You can add another washer (i've seen up to 4) or replace the hub if it's very worn.  The original hub centre is a rubber block cush drive assembly, so it will move a little when ok, but only a little.  If you remove the pressure plate and pack and push the hub backwards you can usually see the wear there.



 
Basket and hub groove wear.  I really don't agree that wear in the basket or hub grooves makes any real difference to how the clutch disengages.  At all.  I have a customer who bought a bike that some idiot had put steel plates into an aluminium basket just before he bought it, and 50,000km later the plates had eaten their way quite a few mm into the basket.  It was all absolutely rooted, but still perfectly functional and lovely to use.  Loud as hell though.

Aluminium baskets that have had aluminium friction plates in them will have a burr on the inside of the basket grooves where the basket has been peened by the plates.  I usually scrape that off - it comes off fairly easily with the carbide scraper.  Not sure if it really makes any difference.
 
Sometimes, the peened out bits of the tangs on the friction plates as in the picture below can get between the steel plates and hold the pack apart and make it slip.  Just grind the peened out bits off and stick it back in.  


To diagnose.  Start at the top and work your way down.  It might be a combination of issues, so don't stop until you've checked it all and fixed every problem you come across.

Wednesday, June 25, 2025

Fuel pump retaining clips in Ducati fuel tanks

 

Turns out, they're called "Terry Clips".  How do I know?  Well.......

A couple of years ago, I sent a rusty 750SS fuel tank out for repair.  It had the rust repaired, and then a liner treatment done.  I've not always been such a fan of the liners.  Done poorly they can lift and cause even more mess, and some of the kits that worked great 25 years ago now just don't.  I try to stay away from them, and certainly won't do it if asked.

digressing.... I did a liner in the mighty KR1S tank back in the day.  It had a small weep from the low point on the LH side - where the water sits when it's on the side stand.  In the instructions, it said to put some nuts and bolts in the tank to act a little more aggressively on the surface rust while you shook it all around like crazy.  Yeah.  Great idea.  You know that little weep you had?  Well, now it's a great big hole you have to weld a plate over.  Awesome.

And then, there was the time someone (let's call him Trev) had to source the chemical that disolves the liner after he'd filled the fuel supply pipe with liner and let it cure.  I think it was MEK?

But I know a bloke who knows a bloke who is very happy to do them, so I take the obvious path to him.

One potential issue though (flagged by another fella who did a few tanks for me, but then decided he'd had enough), is that the treatments used to clean the tanks out may be aggressive on aluminium.  In this case, the rivets that hold the fuel pump mounting clips.  Or don't, when they've been eaten away.

I got this tank back just before Christmas, in the typical end of year rush to get things finished.  I worked over the break, and wanting to get this bike out went to put the tank back together and had a funny feeling something wasn't right.  Couldn't quite put my finger on it though.  When I slipped the pump in, it became pretty obvious.



No clips to hold the pump.  Hmmmmmmmm.  The other shops involved in the repair and liner were closed, so no answers there.  Meaning the question then became "where do I get them?"

And, even more importantly, "what am I trying to find?"  Often, it's the not knowing what to call the thing you're looking for that is the biggest issue.  All these things have names, but often the name is completely irrelevant to what it is or does.  Searched around a bit, and came up with the delightfully random "Terry Clips".  Tel to his mates.  Not sure how I ended up there now, but it's the typical Google this and that and in and out of rabbit holes.  Like this:



20.44.3-1 is the part needed, being 44 - 46mm nominally.  Worked a treat.  But, the next issue was fixing them.  My riveting tools were way to big to get into the tank, and while I considered buying another tool to cut up, I realised there really wasn't enough room anywhere to work it once I'd got it in the tank.  The only alternative I could come up with was screws and nuts, but that presented their own issues.  Screws short enough to not hit the bottom of the tank and damage coating or metal.  And how to hold the nut?

The screws ended up being M3 x 8.  The how being sticky tape, a wee spanner and a clamp to hold the assembly as required, given there's only enough access for one hand.






The typical amount of cussing later, Bob's ya aunty.


And then the pump went back in.

Sunday, April 20, 2025

Hotting up an ST4S - 1026cc, SPS cams, 38mm inlet valves

 I had a bloke ring a few weeks ago and ask about an ST4S ECU upgrade.  I asked him what he was trying to do and he said he had 117hp and would like 130.  I asked what his budget was (gives you an idea of their version of reality), and he replied "a thousand dollars".  I laughed, which wasn't intentional, and probably sounded a bit insulting, but it was an automatic reaction.  It's really not that easy to get a power increase from one of these without spending a lot of money - simply because the bits required cost a lot, as does getting them in.  But sometimes, it's also frustrating, because the expensive bits could just have been fitted at the factory during production.  It's that frustration which, realistically, forms the underlying rant basis of the below rambling. 


Onto the ST4S at hand.  I don't have any before runs to compare to the after run below - I did try to get the bike on the dyno before it came apart, but it's not always easy these days and just didn't come together before I had to pull it apart.  And comparing to all the older runs isn't really practical, as this Dynojet reads lower than the previous ones Dynobike has had.  Realistically, it's probably 12hp or so better at the peak, being nearly 10%.


The thing that has long annoyed me about the ST4 is what it wasn't.  Back then, Ducati had this policy that only the SBK of the day got the best engine, and everything else had to wait for it to trickle down.  So, for 1999 MY, when the SBK was officially named "996" (even though the factory race bikes were first 996cc in 1996 and the 916SPS had been 996cc from 1997), the older 916cc 4V Desmoquattro engine could be used for something else.  Something else being the ST4.  Then, for 2001 MY, when the 996R arrived with the Testastretta 998, the 996cc engine went into the ST.


The problem I have is that the ST4 could have been more, made more annoying that it could've been done with bits off the shelf.  That's what this is here.  Much of the cost involved with this job was related to the age (80k km) and the desire to make it pretty again - painting engines properly is a time and money nightmare.  Any sort of blasting of the cases requires removal of all the bearings, etc, so even if they don't need to be replaced, they're coming out and new ones going in once done.  On this one, every single case and cover was painted.  All those bearings add up. 


The actual hotting up wasn't the big part of the job.  In terms of bits, the 900 crank and SPS cams were on the Ducati shelf in 1999.  As was the 996cc engine.  With the 900 crank fitted - its 68mm stroke is 2mm longer than the 996's 66mm - it has 1026cc, and the marketing department could have played on the concept that stroke = torque and less sporty and the journo's just gobble up shit like that regardless of the truth.  So it's not like they couldn't have claimed it wasn't an SBK engine at all, and a touring special.


The SPS cams?  Well.  The thing is, the SPS cams are most definitely the best Desmoquattro cam they ever made (for a road bike anyway).  For sure, you can find articles like this one - https://www.odd-bike.com/ducati-916-spsps - where they make statements like:


As such the SPS got a reputation as a thundering, maniacal motor that felt way stronger than the dyno numbers would suggest, with a barely-contained fury at lower speeds that made it a bear to ride in slow traffic. Every review reported stalling at idle. Just like any good 916, then. If you meet a 916 owner who claims they are smooth at low speed and easy to ride in traffic, they are either lying or in the process of having a stroke.

which is just complete rubbish.  If you can't make a 916/996SPS idle, you need to stop working on them.  The people responsible for setting up the test bikes certainly needed too. 


We only sold one 1997 916SPS, but we sold quite a few 1998 models and then, for 1999 MY when the 996SPS became a fully complianced road bike in AU, we sold a lot more.  For the 1997 and 1998 models we had to use the Thoroughbred Motorcycles compliance kit originally certified for the 916SP.  But once they came with the normal AU compliance plate, it was happy days.


We were right into playing with cam timing by that time, and we found the same sort of results with the SPS engines as we did with the Biposto engines - advancing the inlet cams gave without taking.  A well set up 996SPS, with the inlet cams advanced 12 degrees and tuned to suit, was, without a doubt, the best engine in the whole range.  Idled like a baby, grandma easy to ride at low speed, went like a rocket (for the time).  Dare I say, it would have made a great sport touring engine.


There's always improvements you can make when reassembling one.  One thing Ducati did then that they appear to have gotten over these days is provide an excessively safe amount of piston to head clearance.  Usually in the 1.4mm range.  That can safely come down to 1.0mm, and these days they're pretty close to that it seems.  On a 98mm bore 996, dropping the squish from 1.4mm to 1.0mm gives a 0.8 point increase in compression ratio just on its own.  Free power right there.  Personally, I aim for 0.95 - 1.00mm on customer bikes, although I'd happily go 0.85 - 0.90mm on my own.  Just make sure it's warm before you spin it to the top.


And if the crank is out, well, why not stick something else in.  The capacity increase with the added 2mm of stroke is only an extra 30cc, which in itself is not really a big deal.  But, that extra 30cc gives an extra 0.3 point increase in comp, so now we're up 1.1 points overall.  Started with 12:1, now we're at 13.14:1.  Daddy loves comp.  Done with std 996 pistons too.  The crank was balanced to suit its new piston and rod mates.  No issues with clearance inside the cases or to the timing shaft (which would have originally been an ST2 part anyway).


The other benefit of the longer stroke is what comes of making it fit.  The first one I did I had some custom 1.2mm base gaskets cut - OEM gasket on a 996 is 0.6mm, plus another 0.6mm to lift the cylinder the required 1mm, minus the 0.4mm of excess squish we wanted to get rid of.  Later, Bruce Meyers told me "I just add another base gasket", which is typically Bruce - simple and effective.  And cheaper - another off the shelf part.  I've done that since.


The advantage here is the head is 0.6mm further away from the crank, and the cams 0.6mm further away from the timing shaft.  So, instead of losing belt tension when you drop the heads to reduce squish with the std crank, you gain belt tension.  Only a little, but it certainly never hurts on these engines.  Some of them can be close to not having enough once the belts have some km on them, even as delivered.


More capacity, more comp, less issues.  


Reshimming everything is always another associated advantage of having them apart.  I typically reduce the crank shimming - I aim for 0.18 - 0.20mm preload with new bearings, and often that seemed to be a reduction of 0.20mm or so from what they came with.


Next it's into the heads.  The 996 and 996SPS cylinder head is the same part.  As are the pistons, meaning that you don't have to worry about machining pistons for piston to valve clearance.  I'm sure Pete Smith had run the inlet cams down to 100 degree centreline on his race engines back in the day with all std bits, so there's plenty there.  But, in this instance, I was fitting some 38mm inlet valves.  So the pistons went off to Special Piston Services to have the reliefs opened a little.  For paranoias sake only, really.


And cams - SPS.  Can be hard to find if you want second handies, as everyone else does too.  Jan at Redfox Grinta was having some made, but I think the grinder may have passed away?  The ones fitted here were Vee Two 604 that I'd had for some time, waiting for a home.  This was as deserving as any.


The std cam timing on the SPS engines was 119/107 centrelines, measured with the belts at the "overtight" 11.5 setting on the Lowener tool.  These days, I've started setting cam timing with the belts at running tension, being 2.5 on the Lowener or 110Hz.  For convenience sake, I'd call 119/107 with tight belts 117/109 with the looser belt setting.  Tom Stalebrandt, who spent a few years working at a Swedish dealer and playing with cam timing as opportunity presented, started retarding exhaust cams and would run the Testastretta Evo engines down to 103 degrees without losing any power, so I followed suit.


On this engine, with belts set to "running tension", I set the cam timing to 104/104 degree centrelines.  To check the timing, I set it up with straight keys in all the cams.  The drop exhaust cam heads fitted to ST and MS4 usually have a 16 degree offset key in the exhaust cams.  From memory the horizontal is advanced and the vertical retarded?  I forget now.  But I checked the timing with straight keys, then pulled the pulleys and headed over to Leigh Farrell's (Cafe Racer) to have him cut some new keyway slots.


For the fuel side, given the ST4S has single injector throttle bodies and I saw no need to complicate matters, I simply replaced the 3 bar fuel pressure regulator with a 3.5 bar part.  The extra 0.5 bar gives an 8% increase in fuel flow, all else being the same.  The change in flow is the square root of the pressure delta, so 3.5 / 3 = 1.167, and square root of that is 1.08.  Or 8%.  From previous testing I know a 996 is potentially fuel flow limited from about 9,500 rpm - see the last graph here https://www.bikeboy.org/duel_inject_throt.html  So I expected that the additional 8% would be fine for this application.


The 3.5 bar pressure regulator used is Bosch part 0280 160 592, and fits in where the Marelli part sits in the fuel pump plate.  Drop in replacement.  So simple, even I made it work.  For a std replacement 3 bar regulator, Bosch 0280 160 560.


I then made up an ECU file based on my ST4S with cam timing, open airbox and mufflers file, with less fuel at the bottom to account for the fuel pressure increase, and a bit more at the top to account for the cams, valves and capacity.  Like that it was pretty good, but once run in went to the dyno for a remap and some numbers.


Which leads me, finally, to the graph.  No before run to compare it to unfortunately, so I'll compare it to the 992cc ST2 job I did around the same time.  Power peaks about 9,350 rpm, which is nice.  Very usable.  And fast.  Standard header pipes, Ducati Performance mufflers, cut airbox lid, maybe a std paper air filter (I'll have to check.), lightened flywheel.  For comparison, the ST2 is externally the same spec.



Owner says in a roll on it happily hangs with his S1000RR mates on the road, which I think came as a surprise to all involved.


The part that annoys me the most is, apart from the 38mm inlet valves, this is off the shelf in 1999 bits.  Nothing special.  Of course, the open mufflers and airbox lid help the peak, but there's no reason they couldn't have delivered a far more serious ST 4V model in 1999 for little effort.


Of course, for the rest of my 1999 MY revisions, the 996 would have SPS cams as well, and the 996SPS would have the 431 inlet cam (1996 996cc factory Corsa) found in the DP catalogue.  The SPS exhaust cam, in terms of area under the curve, is nearing the G cam with much more civilised timing.  It'd do just fine with the 431.


And it would have made the MS4 a whole different animal.  Wheelies into next week.

Thursday, March 20, 2025

Cagiva Raptor TPS baseline procedure - might also work for a TL1000S.

I had a phone call today from a fella asking if I would work on a Cagiva Raptor. Nope was my response - I've just looked and it's 10 years since I've seen a Raptor. Another of the bikes I really never wanted to work on, and am now more than happy to say no to in an effort to simplify my life. But I figured it'd be worth posting this TPS baseline procedure.

The Raptor was somewhat unloved. Great bike, just not wanted. We did a group demo bike ride back in the day with a Raptor, M900ie, 900SSie, 996 and my R1100S I think. The Raptor steered a bit odd - I found getting my weight as far forward as possible helped a lot, as did opening the throttle early. I expect the V-Raptor, with the lower bars and front fairing-ish design, would have been better. It also used a lot less of the front tyre compared to the rear than other bikes. But certainly nice enough for what it was.

Today's bloke was complaining about the "typical" TL1000S 3,000 - 4,000 rpm poor running issue. I suggested he try the TPS baseline we came up with, but he wasn't confident of getting into that sort of thing himself.

Not any sort of official procedure, but we'd been doing TPS baselines for Ducati models for years so it seemed a worthwhile thing to try. I like procedure and repeatability, and this is really the only way to get it. Even if it means they're all bad in the same way, at least then you can start moving forward with some consistancy. The Suzuki ECU in the Raptors didn't have any idle mixture adjustment function, so it was just a matter of manipulating what you had. I believe the Yoshi box could change them, but we never sold enough of the Raptors to make it worthwhile buying one.

From memory (it's a long time since I did any of this, so it's a bit hazy) there was a LCD display on the dash with 3 lines to indicate TPS setting - you'd plug in a diagnostic connector and set the TPS to have the middle line showing with it idling at the desired rpm - I forget what the desired was now. I like things to be more repeatable than that. So, I think we figured out about what the middle line related to in terms of TPS voltage with the throttle blade fully closed on one that ran well, and made it up from there.

Never be afraid to just make shit up, then modify your procedure until it works as hoped.

Procedure was done with the engine not running, back probing the TPS connector with a multimeter to get the voltage reading. We'd generally do it cold, but if it had to be done hot, so be it. The throttle balance set up afterwards was done using the vacuum take offs from the fuel pressure regulator, with all the other vacuum hose guff connected as per normal.

I don't recall if we'd check the idle mixture with the gas analyser now that I think about it. Maybe we did, but as it wasn't anything we could do anything about we didn't bother? Hopefully you'd see 3 to 5% CO - that's where things tend to idle well. But I really don't remember now. Air bleeds were fairly close to full in generally, and winding them out will just lean it out.  We may have been closer to idling too high than too low.

Anyway, good luck, and hope it's of use.
 
 
Raptor / Navigator TPS Setting Procedure

1. Remove airbox, etc, to allow complete access to throttle bodies.

2. Wind idle adjusting knob on LH side off at least two turns.

3. Disconnect throttle linkage at rear butterfly, taking care to remove the plastic washer and spring.

4. Wind rear cylinder throttle stop screw off to allow butterfly to shut completely.  Snap the throttle shut to make sure it can close fully, but have it closed gently with a little push when setting, not jammed.   

(This may have a big rubber cap thingy over it going by photos I have found on line of the throttle bodies.  It's on the other side of the rear throttle body to the TPS)

5. Adjust TPS to give 1.080 volts between brown/black and grey/orange wires – front and centre. The ignition must be turned on to do this.

6. Mark screws with red paint once tightened.

7. Wind idle stop screw back in to give 1.125 volts between the two wires. This is the idle setting.

8. Reconnect throttle linkage.

9. Wind air bleed screws in full closed and set running balance. Connect vacuum gauges to fuel pressure regulator vacuum ports. Leave fuel pressure regulator vacuum lines open. Remove the other vacuum line coming from the rear throttle body next to the fuel pressure reg take off at the check valve on the left hand side and plug. Keep all other vacuum lines/electrical connectors to the airbox, etc connected.

10. Once running balance is set, set idle balance by winding up the idle stop for the front cylinder using the idle adjustment knob. Be sure not to wind idle adjustment knob too far and open throttles off rear cylinder stop screw. This may not result in correct balance, as close as possible is all that is required.

11. Finish idle balance with air bleeds if required. Idle speed should be correct without needing air bleeds to raise speed.

12. Refit all bits.

Monday, May 1, 2023

Ducati DS Cam profile comparison

DS version of the 2V Cam profile comparison -> Click here for link using the same rig as previously modified very slightly to take the M659 head.  And prompting me to buy a new degree wheel.


The DS cams I have to hand are the M659/696/796 8P and the 1100Evo 10B.  George at D Moto sent me a pair of 3V, which are the early 1000 cams.  The later 1000 cams are 7V, and i believe there must also be another version as there are still 3 active # numbers for 1000/1100 cams with the same specs, and one superceded.

The physical difference in the cams from early to late is the large bearing journal on the LH end.  On the later cams it is narrower and further out, and requires a different cam end cap.  As below.  10B on left, 3V on right.


The specs as per the manuals, etc and as measured as below.  I don't have any of the bottom 3 cams to check for now.


I suspect that the 8P and 3V are the same profiles, with the lobe separation opened up (less overlap) for the bigger 1000/1100 engines.  The Evo cam is quite a bit bigger.

Comparing all:


The 8P and 3V.  


And the 3V and 10B, showing how much bigger the Evo's 10B is.

Saturday, April 29, 2023

Multistrada 1000 idling issue - Another (more complete) take on it.

 Some time ago I had a MTS1000 in that had been set up badly to overcome a non idling issue.  That was part of a minor service and not much disassembly, and I got around that electronically.  See here -> MTS 1000 not idling  That particular bike had a very vague history and a couple of dash replacements with no record of actual km.

A bit of MTS1000 info from that report - The MTS1000 was the first Ducati with an idle control valve ("stepper motor", etc).  Any model with an idle control valve doesn't need the air bleeds (the little screws on the sides of the throttle bodies that allow air to bypass the throttle blades) opened, as their primary function is to allow you to set the idle speed.  I also use the air bleeds to equalise the idle mixture between the cylinders, in which case you open the air bleed of the richer cylinder to lean it off to be the same as the leaner cylinder.  Meaning one air bleed should be fully closed.

Seeing air bleeds wound out on bikes with idle control valves really winds me up.  Just not how it's meant to be done.

Recently I had another MTS1000 in for an 80,000km service that I found in the same sort of tune set up - air bleeds wound out one and a half and two and an eighth turns and idle trimmer @ +20.  My response was to wind the air bleeds fully in and set the trimmer to 0 to see what happened, but there was no way it was going to idle successfully.

As I was doing a major service, and had just popped the fuel tank back on to run it, there wasn't a lot of time to be spent pulling it again.  That made it worthwhile to pop off the tank and airbox and have a looksee at the throttle bodies.  As below.




Icky.  But not unexpected for 80,000km, especially on a model where you don't pull the airbox for routine maintenance like you do a Desmoquattro for instance.  None of the 2V models really give you easy access to the throttle bodies to clean them at service.  So I broke out the Threebond Engine Conditioner - which despite the name is a throttle body/intake cleaning spray - and gave it all a good clean up.  I sprayed some down the idle control valve air hose as well, as they can also get claggy.

It's quite awesome for getting fuel residue and combustion gunk off.  I soak carb bits in it, but don't give them too long is my advice.


And Voila!  Lovely.


Back together again, it ended up with both air bleeds still full in and the idle trimmer @ +4, idling happily as desired.